Community Interactions

EMIGRATION

Migratory species such as waterfowl, shorebirds
and caribou adapt to the tundra by avoiding the most severe conditions of
winter. Each year at the end of the short growing season they move southward
into the boreal forest or beyond, but return to the tundra to breed

Aperiodic emigration from the tundra is exhibited by the snowy owl during
those years that the lemming populations have crashed. Those winters see
snowy owl
Irruptions as far south as Virginia. Most owls are found with empty stomachs
and do not survive to return to the Arctic.

The population distribution,
how the organisms are dispersed, is "random,"
not uniform and even, in the tundra

Resource partitioningis dividing
similar resources so that different competing species that need that resource
can coexist.

Competitionfor
resources is tougher in the tundra because of the low availability of resources,
such as nutrients and sunlight.

An interesting phenomenon that is demonstrated more clearly
in the tundra than other biomes arepopulation
cycles.
While one species is at a peak, population wise, its competitor will be between
peaks. An example of this is snowshoe hare and the lynx. The population cycle
is about 3 to 4 years between peaks.

Predator-prey relationshipsin the Tundra follow the normal pattern in whuch the primary
consumers, for example the arctic fox, will eat secondary consumers, for example
birds. The relationship is complicated by the fact the the bird is not only
a prey but a predator. Birds eat grasshoppers and other insects.